QAbstractItemModel实现setRootPath的C++完整代码

以下是使用QAbstractItemModel实现setRootPath的C++完整代码示例：

#include <QAbstractItemModel>
#include <QFileInfo>
#include <QList>
#include <QVariant>

class FileSystemModel : public QAbstractItemModel {
public:
    explicit FileSystemModel(QObject* parent = nullptr) : QAbstractItemModel(parent), rootItem(nullptr) {
        QList<QVariant> rootData;
        rootData << "Name" << "Size" << "Type";
        rootItem = new FileSystemModelItem(rootData);
        rootItem->setFilePath("");
        setupModelData(rootItem);
    }

    ~FileSystemModel() {
        delete rootItem;
    }

    QVariant data(const QModelIndex& index, int role) const override {
        if (!index.isValid()) {
            return QVariant();
        }

        if (role != Qt::DisplayRole) {
            return QVariant();
        }

        FileSystemModelItem* item = static_cast<FileSystemModelItem*>(index.internalPointer());
        return item->data(index.column());
    }

    Qt::ItemFlags flags(const QModelIndex& index) const override {
        if (!index.isValid()) {
            return nullptr;
        }

        return Qt::ItemIsEnabled | Qt::ItemIsSelectable;
    }

    QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const override {
        if (orientation == Qt::Horizontal && role == Qt::DisplayRole) {
            return rootItem->data(section);
        }

        return QVariant();
    }

    QModelIndex index(int row, int column, const QModelIndex& parent = QModelIndex()) const override {
        if (!hasIndex(row, column, parent)) {
            return QModelIndex();
        }

        FileSystemModelItem* parentItem;

        if (!parent.isValid()) {
            parentItem = rootItem;
        } else {
            parentItem = static_cast<FileSystemModelItem*>(parent.internalPointer());
        }

        FileSystemModelItem* childItem = parentItem->child(row);

        if (childItem) {
            return createIndex(row, column, childItem);
        }

        return QModelIndex();
    }

    QModelIndex parent(const QModelIndex& index) const override {
        if (!index.isValid()) {
            return QModelIndex();
        }

        FileSystemModelItem* childItem = static_cast<FileSystemModelItem*>(index.internalPointer());
        FileSystemModelItem* parentItem = childItem->parent();

        if (parentItem == rootItem) {
            return QModelIndex();
        }

        return createIndex(parentItem->row(), 0, parentItem);
    }

    int rowCount(const QModelIndex& parent = QModelIndex()) const override {
        FileSystemModelItem* parentItem;

        if (parent.column() > 0) {
            return 0;
        }

        if (!parent.isValid()) {
            parentItem = rootItem;
        } else {
            parentItem = static_cast<FileSystemModelItem*>(parent.internalPointer());
        }

        return parentItem->childCount();
    }

    int columnCount(const QModelIndex& parent = QModelIndex()) const override {
        if (parent.isValid()) {
            return static_cast<FileSystemModelItem*>(parent.internalPointer())->columnCount();
        }

        return rootItem->columnCount();
    }

    void setRootPath(const QString& path) {
        rootItem->setFilePath(path);
        setupModelData(rootItem);
    }

private:
    void setupModelData(FileSystemModelItem* parent) {
        QString filePath = parent->filePath();
        QFileInfo fileInfo(filePath);
        QDir dir(filePath);

        QList<QVariant> data;
        data << fileInfo.fileName();

        if (fileInfo.isFile()) {
            data << fileInfo.size();
            data << fileInfo.suffix();
            parent->setData(data);
            return;
        }

        data << "";
        data << "Folder";
        parent->setData(data);

        QList<QVariant> row;
        QFileInfoList fileList = dir.entryInfoList(QDir::Files | QDir::NoDotAndDotDot, QDir::Name);

        for (const QFileInfo& fileInfo : fileList) {
            row.clear();
            row << fileInfo.fileName() << fileInfo.size() << fileInfo.suffix();
            FileSystemModelItem* item = new FileSystemModelItem(row, parent);
            item->setFilePath(fileInfo.filePath());
            parent->appendChild(item);
        }

        QFileInfoList folderList = dir.entryInfoList(QDir::Dirs | QDir::NoDotAndDotDot, QDir::Name);

        for (const QFileInfo& folderInfo : folderList) {
            row.clear();
            row << folderInfo.fileName() << "" << "Folder";
            FileSystemModelItem* item = new FileSystemModelItem(row, parent);
            item->setFilePath(folderInfo.filePath());
            parent->appendChild(item);
            setupModelData(item);
        }
    }

    FileSystemModelItem* rootItem;
};

class FileSystemModelItem {
public:
    explicit FileSystemModelItem(const QList<QVariant>& data, FileSystemModelItem* parent = nullptr) : parentItem(parent), itemData(data) {
    }

    ~FileSystemModelItem() {
        qDeleteAll(childItems);
    }

    void appendChild(FileSystemModelItem* child) {
        childItems.append(child);
    }

    FileSystemModelItem* child(int row) {
        return childItems.value(row);
    }

    int childCount() const {
        return childItems.count();
    }

    int columnCount() const {
        return itemData.count();
    }

    QVariant data(int column) const {
        return itemData.value(column);
    }

    FileSystemModelItem* parent() {
        return parentItem;
    }

    int row() const {
        if (parentItem) {
            return parentItem->childItems.indexOf(const_cast<FileSystemModelItem*>(this));
        }

        return 0;
    }

    void setData(const QList<QVariant>& data) {
        itemData = data;
    }

    QString filePath() const {
        return m_filePath;
    }

    void setFilePath(const QString& filePath) {
        m_filePath = filePath;
    }

private:
    QList<FileSystemModelItem*> childItems;
    QList<QVariant> itemData;
    FileSystemModelItem* parentItem;
    QString m_filePath;
};

在此示例中，我们定义了一个FileSystemModel类，它继承自QAbstractItemModel，并实现了setRootPath方法。setRootPath方法接收一个路径作为参数，并使用该路径更新根项的文件路径，然后调用setupModelData方法重新设置模型数据。setupModelData方法解析文件夹并将其添加到模型中作为子项。注意，列数据是使用QList<QVariant>传递的，这样我们可以在列中使用不同的数据类型。此外，我们还定义了一个FileSystemModelItem类，它表示模型中的一个项目。每个项目都有一个文件路径，并且可以有多个子项。